DeclarativeColumnsMetaclass.__new__ should super-call

[mwhudson]

If you want a subclass of Table to have a metaclass such as ABCMeta, you need to subclass both DeclarativeColumnsMetaclass and the other class. Because DeclarativeColumnsMetaclass just calls type.new rather than super(DeclarativeColumnsMetaclass, cls).new, you have to be more careful about the order you subclass things that you should have to be.

Luckily the fix is trivial :-)

[bradleyayers]

Thanks for this, I merged in your patch.